Microstructures, Electrical, Thermal, and Mechanical Properties of Bulk Ti2AlC Synthesized by Self-Propagating High-Temperature Combustion Synthesis with Pseudo Hot Isostatic Pressing

The microstructure and the electrical, thermal, and mechanical properties of bulk Ti2AlC synthesized by self-propagating high-temperature combustion synthesis with pseudo hot isostatic pressing (SHS/PHIP) were investigated in detail. The plate-like Ti2AlC grains distribute irregularly, with the grain size of around 6 mu m in length and 1 mu m in width. With increasing temperature, the electrical resistivity increases linearly from room temperature (RT) to 900 degrees C, but the thermal conductivity decreases slightly. The RT electrical resistivity and thermal conductivity are 0.40 +/- 0.03 mu Omega center dot m and 27.0W center dot(m center dot K)-1, respectively. The electronic component of the thermal conductivity is the dominant mechanism at all temperatures, and the phonon contribution almost can be neglected above 873K. With increasing temperature, the flexural strength increases first, then decreases above 550 degrees C, at which it reaches the maximum value of 539 +/- 36 MPa. The brittle-to-plastic transition temperature falls in the temperature range of 750 degrees C-950 degrees C. The Ti2AlC synthesized by SHS/PHIP process exhibits an anisotropic compressive strength. The work of fracture of Ti2AlC is estimated to be 200 +/- 7J/m2, which is much higher than that of traditional ceramics.